Heat exchanger including tube expansion means



April 30, 1968 M. w. KAYE 3,380,516

HEAT EXCHANGER INCLUDING TUBE- EXPANSION MEANS Filed June 17, 1966 I 2 Sheets-Sheet 1 INVENTOR. M/I fd/I/ /4./ MJ

M. W. KAYE April 30, 1968 HEAT EXCHANGER INCLUDING TUBE EXPANSION MEANS Filed June 17, 1966 2 Sheets-Sheet 2 INVENTOR. /////V/'0/t /1/. 4441 5 United States Patent 3,380,516 HEAT EXCHANGER INCLUDING TUBE EXPANSION MEANS Mlnton W. Kaye, Pasadena, Calif., assignor to Raypak Company, Inc., a corporation of California Filed June 17, 1966, Ser. No. 558,361 1 Claim. (Cl. I6581) ABSTRACT (IF THE DISCLOSURE A heat exchanger having spaced elongated integral headers held spaced apart by tie rods at their ends. Tubes extend between the headers and into openings having O-ring seated in internal grooves. Each header is provided with longitudinal fianges on opposite sides for sealing engagement with portions of a firebox.

This invention relates to improvements in tube type heat exchangers. In the exemplary form of the invention described herein, it is embodied in a finned tube exchanger used in a water heatin unit or boiler.

Tube type heat exchangers and boilers are of course well known in the prior art. These heat exchangers and/ or boilers as typically constructed, present certain problems and disadvantages. Conventional heat exchangers or boilers of this type characteristically present a fairly typical construction. Tubes are provided which extend between relatively heavy or massive tube sheets having openings to receive the ends of the tubes. The ends of the tubes are rolled, that is, they are expanded into a very tight holding fit in the holes or openings in the tube sheets. Headers are provided at the ends of the tubes having holes or openings which register with the ends of the tubes. The headers are clamped against the tube sheets and gaskets are used between the headers and the tube sheets to seal around the ends of the tubes. The headers must of course be firmly clamped to the tube sheets since otherwise the pressure would of course force the headers away from the tube sheets.

The typical construction as described has a number of disadvantages. Among these is that the tube sheets are of relatively heavy massive construction. The openings in the headers must be sealed to the ends of the tubes in the tube sheets. Replacement of tubes is difficult since the tube must be cut off and then the end of it reamed out from the hole into which it has been expanded. Another disadvantage is that the different tubes are subject to different degrees of expansion and contraction from temperature with the result that some are put into compression and some into tension, thus creating a distorting etfect. Such a boiler constructed in this way is not adapted to have parts of its inoperative while other parts are operating, by reason of the difference in compression and tension in the tubes.

The herein invention is intended to overcome all of the foregoing disadvantages and make possible a much better and less expensive boiler or heat exchanger. In this invention, the tube sheets are eliminated entirely. The ends of the tubes fit into bushings formed directly in the headers, and inside of these bushings are annular grooves having sealing O-rings in them. The O-rings are capable of sealing the tubes effectively even at very high pressures. The headers are bolted directly to each other, that is, they are held together by tie rods and spacer sleeves. No tube sheets are required at all. Replacement of a tube is extremely easy. As a matter of fact, the replacement of a tube is so easy that when the structure is taken down to replace a tube, it is convenient to replace all of them at that time. The mounting of the tube ends form expansion joints with the tube ends floating in the joint. Therefore, differ- 3,380,516 Patented Apr. 30, 1968 ent tubes can expand or contract in different amounts without any tubes being placed either in tension or compression. Thus, it is possible to operate only a part of the heat exchanger or boiler without operating the other part and without entailing damage to the unit. Another advantage is that the plumbing thrust, i.e., the thrust that occurs in the plumbing connection themselves, is taken care of by the holding connection between the headers.

From the foregoing, the specific objects of the invention will be readily apparent to those skilled in the art and may be briefly summarized as follows:

The primary object is to provide a superior, but less expensive heat exchanger or boiler.

Another object is to provide a construction in which conventional tube sheets are entirely eliminated.

Another object is to provide a construction in a tube heat exchanger wherein the tube ends are mounted in expansion joints so as to permit free expansion and contraction of individual tubes and to greatly facilitate replacement of tubes. A corollary to this object is to provide a construction wherein the tube ends are mounted in bushings in the headers and sealed by way of O-rings.

Another object is to provide a construction having the foregoing objects wherein the headers are attached and secured to each other by way of tie rods and spacers.

Further objects and additional advantages of the invention wil become apparent from the following detailed description and annexed drawings wherein:

FIGURE 1 is a diagrammatic view of a boiler or heating unit embodying the improved construction of the invention;

FIGURE 2 is a plan view of a heat exchanger embodyin g the invention;

FIGURE 3 is a detail view of a modified form of tie rod assembly between the headers;

FIGURE 4 is a partial view showing the mounting of the heat exchanger in the heater unit;

FIGURE 5 is a typical cross section through one of the headers;

FIGURE 6 is a detail sectional view taken along the line 66 of FIGURE 5.

Referring now or particularly to FIGURE 1 of the drawings, this figure shows a typical heating or boiler unit 10. It is housed in a housing or cabinet 12 which may be of sheet metal construction. The construction shown is exemplary and in this embodiment, the heater or boiler is gas fired. Numeral 1.4 designates a gas inlet line having branches 16 and 17 connecting to gas manifolds 2t) and 21. In the branch lines are electric gas valves 22 and 23. Manifold has branch connections 27, 28, and 29 connecting to a group of gas modulating valves, Manifold 21 has branch connections 31, 32, and 33 connecting to another group of gas valves.

The heating unit has a fire box as designated at 37. The heat exchanger of the invention is mounted in the upper part of the combustion chamber and is designated generally at 40. It is shown in plan in FIGURE 2. Numeral 4'1 designates a stack or an outlet pipe at the top of the cabinet or housing 12 having a conventional hood 42. Numeral designates a water inlet pipe to the heat exchanger, having a manual valve 46 in it, and numeral 47 designates a water outlet pipe.

Having reference to FIGURE 2, the unit comprises an inlet header 50 and an outlet header 51. In the exemplary form of the invention, these headers have a cross section having a shape as shown in FIGURES 4 and 5. The inlet header 5%) has a fitting 53 to receive the inlet pipe 45 and the header 51 has a fitting 55 to receive the outlet pipe 47. The heat exchanger may be constructed to provide for a single pass of water therethrough, or multiple passes if desired. The inside face of the header 50 as designated at 58, is flat and similarly the inner face of the header 3 51 is flat as shown at 60. The face 58 forms a flange as shown in FIGURES 4 and 5, the edges of which have a slight taper as shown. The part 60 has a similar construction.

FIGURE 4 illustrates the mounting of the heat exchanger unit in the heater unit 12. Numerals 63 and 64 designate walls of the fire box which may of course be made of flame resistant material. At the tops of these walls are metal caps 66 and 67 made of suitable material. Resting on these cap members at the inner edges thereof, are channel members 70 and 71 made of suitable material, these members having pads in the bottom thereof of asbestos material, as designated at 73 and 74. The flange member 58 and 60 rest on the pads 73 and 74 in the channel members 70 and 71.

The upper part or top of the housing or cabinet 12 is designated at '77 in FIGURE 4. It has vertical side parts 78 and 79 to which are attached inverted channel members 82 and 83 having asbestos pads therein as designated at 85 and 86, which rest on the top edges of flanges 58 and 60.

The headers 50 and 51 are held together by tie rods, two of which are shown at 90 and 91 in FIGURE 2. The flange 58 has openings or eyes therein, one of which is designated at 93 in FIGURE 4 to receive the ends of the tie rods. Flange 60 has similar eyes or openings. The tie rods are threaded at the ends where they extend through the eyes and are secured to the fianges by nuts. Tie rod 90 is secured by nuts 96 and 97 at one end and nuts 98 and 99 at the other end. Tie rod 91 is secured by nuts 102 and 103 at one end, and nuts 104 and 105 at the other end.

FIGURE 3 shows a slightly modified form of securing means between the headers. In this modification a sleeve 107 is provided around the tie rod 91 which acts as a spacer between the flanges 58 and 60. Only one nut 102 is used adjacent to flange 58 and one nut 105 at the other end.

FIGURES and 6 show the construction of the header 50 in more detail. At the position of flange 58, the header has greater thickness and it has aligned openings 110 forming bushings 118 to receive the ends of the tubes, one of which is designated at 111. The bore 110 of the bushing has an annular groove 113 in which is received an O-ring 114 into which the end of the tube 111 fits. The tubes may be finned tubes of conventional construction having fins as shown at 116.

The mounting of the ends of all of the tubes in both headers is like that just described. It will be observed that the mounting of the ends of the tubes form expansion joints. Each tube is individually free to expand and contract in accordance with temperature Without effecting the security of the seal formed at its ends. In other words, although the headers are secured and held together in fixed relationships, the tubes can individually expand and contract, being accommodated in this by the expansion joints formed at their ends.

From the foregoing, those skilled in the art will fully understand and appreciate the nature and characteristics of the invention and that it accomplishes and realizes each of the objects and advantages as enumerated in the foregoing, as well as having additional advantages that are apparent from the detailed description.

The disclosure herein is representative of a preferred exemplary form of the invention. The invention may be embodied in various other heat exchanger constructions and other specific types of expansion joints may be utilized. It is intended that the disclosure be illustrative rather than limiting, and that the invention be accorded the full scope of the claim appended hereto.

What is claimed is:

1. A heat exchanger comprising: first and second elongated hollow integral headers; tie rod means extending through integral ears at the ends of said headers and holding the same in predetermined spaced relation; aligned openings in the facing portions of said headers; a circumferential groove in each opening; an O-ring seal in each groove; tubes extending between said headers, into said openings and sealingly engaging said O-rings; and an outwardly directed integral longitudinal flange extending substantially continuously along each opposite side or" each of said headers, said flanges extending generally perpendicular to the length of said tubes.

References Cited UNITED STATES PATENTS 1,271,135 7/1918 Coltrin -1 165-449 911,156 2/1 09 Politz 165-173 X 1,962,909 6/1934 Price 165-81 X 2,161,019 6/1939 Coy l175 X 2,793,836 5/1957 Holmes -475 X 3,279,532 10/1966 Pfeil 165-81 FOREIGN PATENTS 979,366 1/1965 Great Britain.

ROBERT A. OLEARY, Primary Examiner. M. A. ANTONAKAS, Assistant Examiner. 

